V cholerae

Tamplin et. al. (54) observed that V. cholerae and A. hydrophila cell extracts contained substances with TTX-like biological activity in tissue culture assay, counteracting the lethal effect of veratridine on ouabain-treated mouse neuroblastoma cells. Concentrations of TTX-like activity ranged from 5 to 100 ng/L of culture when compared to standard TTX. The same bacterial extracts also displaced radiolabelled STX from rat brain membrane sodium channel receptors and inhibited the compound action potential of frog sciatic nerve. However, the same extracts did not show TTX-like blocking events of sodium current when applied to rat sarcolemmal sodium channels in planar lipid bilayers. 

Cholera, the first reportable disease, is endemic in South Asia, particularly in the Ganges delta region.2 The biotypes of Vibrio cholerae responsible for pandemics are serogroup 01 (El Tor) and serogroup 0139.16,17 Cholera can be transmitted by water or by food contaminated with contaminated water, particularly undercooked seafood. V. cholerae grows well in warm temperatures, causing marked seasonality in the incidence of cholera.2... 

V. cholerae is a gram-negative bacillus. Vibrios pass through the stomach to colonize the upper small intestine. Vibrios have filamentous protein extensions that attach to receptors on the intestinal mucosa, and their motility assists with penetration of the mucus layer.2 The cholera enterotoxin consists of two subunits, one of which (subunit A) is transported into the cells and causes an increase in cyclic AMP, which leads to a deluge of fluid into the small intestine.20 This large volume of fluid results in the watery diarrhea that is characteristic of cholera. The stools are an electrolyte-rich isotonic fluid, the loss of which results in blood volume depletion followed by low blood pressure and shock.2 Of note, the diarrheal fluid is highly infectious. 

The cornerstone of cholera treatment is fluid replacement. Without treatment, the case-fatality rate for severe cholera is approximately 50%. For cholera, rice-based ORT is better than glucose-based ORT because it reduces the number of stools.21 Patients with significant disease should receive a short antibiotic course, 1 to 3 days, to shorten the duration of illness and decrease the number of stools. Doxycycline 300 mg once daily is the drug of choice. Other antibiotics shown to be effective include erythromycin, azithromycin, trimethoprim-sulfamethoxazole, and ciprofloxacin.2 Antibiotic resistance has been documented in V cholerae since 1977.2 Antibiotic prophylaxis is not warranted. 

V. cholerae B subunits of the cholera toxin (CTB) Potato Receptor-binding activity. Immunogenic in mice when delivered orally. Mice challenged intraileally with CT showed up to 60% reduction in diarrheal fluid accumulation in small intestines. 117, 118... 

V. cholerae B subunits of the cholera toxin (CTB) Tobacco leaf chloroplast No immunogenicity assays performed. 119... 

Enterotoxigenic E. coli epitope and rotavirus epitope fused to CTB Potato tuber Mice developed detectable levels of serum and intestinal antibodies. Immunogenic in mice against ETEC, rotavirus, and V. cholerae when delivered orally. Symptoms reduced in passively immunized mouse neonates following rotavirus challenge. 63... 

Hepatitis C virus (HCV) HVR1 epitope fused to V. cholerae CTB Tobacco leaf Reacted with HRVl-specific monoclonal antibodies and sera from individuals infected with HCV. HVR1 epitope formed fused to CTB was immunogenic in mice when administered nasally. 62... 

CDC Case Definition An illness characterized by diarrhea and/or vomiting severity is variable. Laboratory criteria for diagnosis is (1) isolation of toxigenic (i.e., cholera toxin-producing) V. cholerae Ol or0139 from stool orvomitus or (2) serologic evidence of recent infection. 

Brachyspira hyodysenteriae, Pasteurella haemolytica, P. aeruginosa, V. cholerae and Y. enterocolitica [156-158,164]. 

Scheme 9.11 Enzymatic transsialylation of four MPEG-DOXyl glycosides with sialidases from Vibrio cholerae and Salmonella typhimurium. V. cholerae sialylated in position 6 of the terminal monosaccharide units with yields of 12-17%, whereas S. typhimurium sialylated position 3 of the same monosaccharide units (yields 14-24%).

Treatment — Because of the severe dehydration caused by cholera infection, the most important therapy is fluid and electrolyte replacement. Many antibiotics are effective against V. cholerae, including tetracycline, doxycycline, ciprofloxacin, and erythromycin.3... 

The increased incidence of food-borne diseases from shellfish contaminated with Vibrio species have brought forward renewed interest in irradiation of shellfish and other seafood. Results are very promising for clams and oysters without killing the molluscs [65]. The radiation decimal reduction dose (Dio) determined for Vibrio cholerae 01 biotype El Tor inoculated into various molluscs was 0.14 kGy [66]. Similar radiation sensitivity of this organism was found in inoculated fish fillets and shrimp tails [67]. The radiation dose to eliminate as high as 10 CFU/g Vibrio spp. in oysters was 1.2 kGy [68]. The radiation Dio value for V. cholerae 01 biotype El Tor in marine snails was 0.11 kGy [69]. 

Complete desialylation of erythrocytes is not necessary for erythrocyte sequestration liberation of 15-20% of membrane sialic acids was found to be sufficient for a significant diminution of the life-time of erythrocytes.481,482 For an in vitro system with rat-peritoneal macrophages (see later), this threshold value was found to be only 10% when using soluble V. cholerae sialidase, but it was —30% when the erythrocytes were treated with the same enzyme immobilized on Sepharose.488... 

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